#include <bits/stdc++.h>
using namespace std;

void solve() {
  int N;
  long long X;
  cin >> N >> X;
  unordered_map<long long, long long> dp, ep;
  dp[0] = 0;
  for(int i = 0; i < N; i++) {
    int c;
    cin >> c;
    long long x = X & ((1LL << c) - 1);
    long long y = X & (1LL << c);
    if(y != 0) continue;
    for(const auto [l, r] : dp) {
      long long l2 = - 1 - x;
      long long r2 = (1LL << c) - x;
      if(r2 > r) ep[l] = r2;
      else ep[l] = r;
      if(X < (1LL << c)) continue;
      if(l2 < l) ep[l2] = r;
      else ep[l] = r;
    }
    swap(dp, ep);
    ep.clear();
  }
  long long ans = 3LL << 60;
  for(const auto &[l, r] : dp) {
    ans = min(ans, 2 * (r - l));
  }
  cout << ans << "\n";
}

int main() {
  int T;
  cin >> T;
  while(T--) solve();
}